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Nuclear Theory·nucl-th

Wednesday·April 24, 2024

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    Shell-model study of Si: coexistence of oblate, prolate and superdeformed shapes

    Dorian Frycz🇪🇸 · Javier Menéndez🇪🇸 · Arnau Rios🇪🇸 · Benjamin Bally🇫🇷 · Tomás R. Rodríguez🇪🇸 · Antonio M. Romero🇪🇸

    We study the shape coexistence in the nucleus Si with the nuclear shell model using numerical diagonalizations complemented with variational calculations based on the projected generator-coordinate method. The theoretical electric quadrupole moments and transitions as well as the collective wavefunctions indicate that the standard USDB interaction in the shell describes well the ground-state oblate rotational band, but misses the experimental prolate band. Guided by the quasi-SU(3) model, we show that the prolate band can be reproduced in the shell by reducing the energy of the orbital. Alternatively, in the extended configuration space a modification of the SDPF-NR interaction that accommodates cross-shell excitations also reproduces the oblate and prolate bands. Finally, we address the possibility of superdeformation in Si within the space. Our results indicate that superdeformed structures appear at about -~MeV.

    nucl-thnucl-exPRC(2024)·9 citations
  2. 02

    Parameter dependence of the -decay properties of neutron-rich Zr isotopes within the interacting boson model

    M. Homma · K. Nomura

    We investigate parameter dependence of the calculated -decay properties, as well as low-lying states for the neutron-rich Zr isotopes within the neutron-proton interacting boson model (IBM-2) and interacting boson-fermion-fermion model (IBFFM-2). It is shown that the calculated values for the transitions of the ground states of the parent even-even nuclei Zr into the states of the daughter odd-odd nuclei Nb consistently exhibit a strong dependence on those parameters associated with the quadrupole-quadrupole boson interaction, and with the residual interaction between an unpaired neutron and an unpaired proton in the IBFFM-2 Hamiltonian for the odd-odd Nb nuclei. By the reduction in magnitude of the quadrupole-quadrupole interaction strength by approximately a factor of 2, the calculated values for the ZrNb transitions increase and agree with the experimental values. This points to a significant improvement over the previous study performed in the same mass region, that consists of the mapping from a relativistic energy density functional calculation onto the IBM-2 Hamiltonian.

    nucl-thnucl-exPRC(2024)·5 citations
  3. 03

    HESS J1731-347 is likely a Quark Star Based on the Density-Dependent vMIT Bag Model

    Min Ju🇨🇳 · Pengcheng Chu🇨🇳 · Xuhao Wu🇨🇳 · He Liu🇨🇳

    In this study, we extend the MIT bag model by incorporating the vector interaction among quarks and introducing a density-dependent bag pressure.Then we proceed to investigate the thermodynamic properties of strange quark matter (SQM) and pure up-down quark matter (udQM) in quark stars (QSs).Our findings demonstrate that the density dependence of bag pressure and the vector interaction among quarks can significantly stiffen the equation of state (EOS) for both SQM and udQM which allows for the description of massive compact stars such as those observed in GW190814 and PSR J0740+6620 as plausible candidates for QSs.Ultimately, we derived a series of mass-radius relations of QS based on several combinations of (, ). Our results support the hypothesis that HESS J1731-347 is a quark star.

    nucl-th6 citations
  4. 04

    Nuclear mass predictions based on convolutional neural network

    Yanhua Lu · Tianshuai Shang · Pengxiang Du · Jian Li · Haozhao Liang · Zhongming Niu

    A convolutional neural network (CNN) is employed to investigate nuclear mass. By introducing the masses of neighboring nuclei and the paring effects at the input layer of the network, local features of the target nucleus are extracted to predict its mass. Then, through learning the differences between the experimental nuclear masses and the predicted nuclear masses by the WS4 model, a new global-local model (CNN-WS4) is developed, which incorporates both the global nuclear mass model and local features. Due to the incorporation of local features, the CNN-WS4 model achieves high accuracy on the training set. When extrapolating for newly emerged nuclei, the CNN-WS4 also exhibits appreciable stability, thereby demonstrating its robustness.

    nucl-thPRC(2025)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE